The field of the invention relates generally to turbine engines and, more particularly, to methods and systems for estimating operating parameters for controlling a turbine engine.
In at least some known turbine engines, engine performance and operability is determined using operating parameters of the engine. At least some of these operating parameters are un-measurable parameters, for example, parameters that cannot be measured by sensors, such as thrust and/or stall margin, and/or that are impractical to measure using sensors, such as combustor exit temperature and/or turbine inlet temperature.
At least some known engine control systems indirectly control and/or monitor un-measurable operating parameters by using measured quantities, such as a corrected fan speed, an engine pressure ratio, and/or corrected fuel (“phi”) schedules. However, because un-measurable operating parameters inferred or estimated from such measured quantities may not be very accurate, large design margins are used for gas turbine engines that include such known control systems. Large design margins may reduce the performance and/or condition of the gas turbine engine. As such, there is a need to more accurately determine the un-measurable operating parameters of a gas turbine engine.